Patent GB-968538-A (GB)
Title: Push button type telephone calling device
IPC: H04M1/274
Filed: 1960-09-16
Abstract: 968,538. Impulse transmitters. OKI ELECTRIC INDUSTRY CO. Ltd. Sept. 16, 1960 [Sept. 16, 1959], No. 32003/60. Heading H4K. A push-button telephone calling device comprises push-button operated plates A K  (Fig. 1) each provided with two series of lead conductors, one series L 1 , L 2  . . . &c. representing the individual digits which may appear in a call sign and the other series LL 0 , LL 1  . . &c. representing pulse values of said digits. A point or points of interconnection t 1 , t 2 , t 3  is or are provided between a conductor or conductors of one series and a conductor or conductors of the other series of each plate according to the call sign particularized by that plate. Pulsing means is adapted to act under the control of a selected plate and is such that when a number of pulses according to the call sign particularized by the particular plate has been emitted, the pulsing means will be short-circuited through interconnected conductors of the selected plate. The interconnections t 1 , t 2 , t 3  are eyelets and the lead conductors are provided by a printed circuit technique. The plates A K  slide in guides 21 in a casing (Fig. 4, not shown) and when the button AA attached to plate A K  is pressed the relevant plate is held down against the action of springs S by a hook P K  on a lock plate P. Conductive levers b 0 , b 1 , b 2  . . . and C 1 , C 2 , C 3  are moved and projections 23 and 24 thereon conductively engage the lead conductors LL 0 , LL 1 , LL 2  . . . and L 1 , L 2 , L 3  . . . respectively of the selected plate A K . A projection 39 on lever C n  closes a switch 40 to start a motor M which sets in motion a spindle 41 to rotate a contact member g and index a contact member h.- Levers b 0 , b 1 , b 2  are electrically connected through spring strips e 0 , e 1 , e 2  to conductors 27 which connect through conductors U to printed conductors G (see also Fig. 3) on an insulating plate 25. Similarly, levers C 1 , C 2 , C 3  . . . are electrically connected through spring strips f 1 , f 2 , f 3  to conductors 28 which connect through conductors W to conductors H on plates 25. Operation is explained with reference to the diagram of Fig. 2. The plate 25 is provided with separate contacts connected in series by lead U c . The movable contact member g is adapted to move over the plate 2 when the pulses of a selected call sign are to be transmitted. Contact member g successively completes a circuit through each of said separate contacts and progressively comes into contact with lead conductors u 0 , u 1 , u 2  . . . . Contact member h is indexed over the surface of plate 25 when the pulses are to be emitted and-during the course of its indexing movement maintains contact with lead w c  and successively comes into contact with leads w 1 , w 2 , w 3  . . . . Each index movement corresponds to a change of digit. Leads u 0 , u 1 , u 2  . . . are respectively connected to leads LL 1 , LL 2 , LL 3  . . . on plate A K . Leads w 1 , w 2 , w 3  are respectively connected to leads L 1 , L 2 , L 3  on plate A K . When, for each digit, a number of pulses as determined by plate A K  has been transmitted by successive contact of contact member g with the separate contacts, the circuit between terminals 1, 2 is shorted by interconnected leads of plate A K  until contact member h is indexed to transmit pulses corresponding to the next digit. After transmission of a call sign a lobe 45a (Fig. 1) on cam 45 rocks a lever 46 to restore lock plate P, thereby releasing plate A K . Motor M is switched off by switch 40 controlled by projection 39 on lever C n .